FR2817165A1 - ORGANIC DEEMULSIZING FORMULATION AND ITS USE IN THE TREATMENT OF DRAINS DRILLED IN OIL MUD - Google Patents

Abstract

A demulsifying formulation in organic base, usable in the treatment of drains drilled in oil mud, non-eco-toxic and best compatible with the formation fluids, comprises: - at least one constituent chosen from non-ionic amphiphilic compositions obtained by reaction of at least one vegetable oil, optionally polymerized, on at least one amino alcohol, and the alkyl esters (for example from C1 to C8) of fatty acids derived from natural, vegetable or animal oils; - optionally at least one wetting agent; - and optionally at least one solvent; - the whole being mixed in an organic base.

Description

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  ORGANIC DEEMULSIZING FORMULATION AND USE THEREOF

  IN THE TREATMENT OF DRAINS DRILLED IN OIL MUD

Field of the invention

  The invention relates to the treatment of drains drilled in oil mud.

  It relates more particularly to a demulsifying formulation, usable in the treatment of drains drilled in oil mud, preferably non-eco-toxic and best compatible with the formation fluids, which comprises at least one constituent chosen from non-amphiphilic compositions -ionics obtained by reaction of at least one vegetable oil, optionally polymerized, on at least one amino alcohol, and the alkyl esters (for example from C1 to C8) of fatty acids derived from natural, vegetable or animal oils; optionally at least one wetting agent; and optionally at least one solvent (or diluent); said demulsifying formulation being used as an organic base in order to minimize the phenomena of emulsion formation in situ and

  of re-saturation in aqueous phase of the surroundings of the well.

  Technological background An oil formation is damaged when a well proves to be less productive than the well test analyzes predicted. The damage mechanisms of the formation depend on the type of reactions produced between the well fluid, the formation fluids and the rock, under the working conditions (pressure and temperature of the layer and the mud). The alteration of the producing formation close to the well is due to the harmful interactions between the formation fluids and the foreign fluids introduced. If the well fluids prove to be responsible for the damage, chemical treatment is then necessary to restore the characteristics of the reservoir. It must make it possible to destroy the external and / or internal cake and to clean the damaged area around the

  well. This treatment may or may not be combined with an acid type matrix treatment.

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  Generally, oil-based well fluids generate little filtrate, have good rheological properties, and form a thin, permeable cake. On the other hand, they contain chemical additives (surfactants) responsible for emulsifying water in the form of droplets within the continuous oil-based phase and making the solid particles used as an additive or viscosifier wettable with oil. These surfactants in large excess concentration in the fluid to maintain the stability of the emulsion

  reverse can enter the formation with the filtrate.

  Three types of damage are particularly possible in the case of oil-based fluids: * the formation of an emulsion within the tank, resulting from interactions between the filtrate from the oil mud (which mainly contains l oil and

  surfactants) and reservoir fluids (brine and oil). Intrinsic emulsifiers

  excess amounts in the formulation may come into contact with the formation. However, a significant shear at the constriction of the pores in the presence of emulsifier

  can lead to the formation of a very stable and very viscous emulsion

  reducing the effective mobility of the hydrocarbons present; * an alteration of the initial wettability of the reservoir rock. The emulsifier type products generally transform the rock initially wettable with water into a state of intermediate wettability, or even wettable with oil, which can cause a modification of the permeability relative to the oil and therefore decrease the mobility of the 'oil; and

  * the deposit of fine moving particles in the pores (reduction of permeability

absolute integrity).

  The chemical composition of the filter cake must be carefully considered when designing the treatment fluids. The cake mainly consists of emulsified water droplets, which act as colloidal particles and combine with the solid particles in suspension in the fluid to form a cake. The stability of

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  the emulsion, the type and the nature of the solids influence both the fluid losses and the filtering properties of the cake. The choice of treatment product must take into account

  the parameters necessary for washing the cake and leaching the formation.

  The envisaged treatment concerns: * the dissolution or dispersion of the weighting agents present in the cake and

  * The attack of the additives contained in the filtrate.

  The treatment must therefore be adapted to the type of mud used. The main parameters to consider are: * the type of damage and its extent; * the characteristics of the tank (porosity and permeability); * the type of formation (nature of the rocks and acid solubility); * possible contaminants (water, sludge - water mud and oil mud -, cements, bacteria); * the compatibility of the treatment fluid with the contaminants; * background pressure and temperature; * processing time; and

  * physical limitations of well equipment.

  Improving the design of a drilling fluid to reduce damage can be completely ruined by the use of a procedure and / or a cleaning product

  unsuitable. The oil sludge cake processing solutions offered today-

  ment are in aqueous form and generate considerable additional damage, or even lead to clogging of the well. Numerous examples of treatment of drains using surfactants used in the aqueous phase can be found in the literature (US Pat. Nos. 4,681,165, 4,595,511, 4,681,164 and 5,110,487). The use of oil-based surfactants for the breaking of emulsions has been postponed (US Pat. Nos. 5,614,101, 256,305 and 4,416,754), but the objective is not the application to setting oil production.

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  Summary of the invention The subject of the present invention is a demulsifying formulation used as an organic base (preferably in a non-polluting organic base and which may be the oil of the mud itself), said demulsifying formulation being capable of breaking a water-in-oil emulsion. The invention also relates to the use of an organic base demulsifying formulation in the treatment of drains drilled in mud to

  oil. The simplification of the treatment solution makes it possible to limit the effects of re-

  saturation in aqueous phase around the well and the formation of emulsions in situ.

  Detailed description of the invention

  The organic base demulsifying formulations of the invention are characterized in that they comprise at least one constituent (hereinafter designated

  description by "demulsifying agent" or "emulsion breaker"), possibly

  associated with a wetting agent and at least one solvent (or diluent), the whole being

  mixture in an organic base. comprising at least one non-amphiphilic compound

  ionic obtained by reaction of at least one vegetable oil, optionally polymerized, on at least one amino alcohol, and / or at least one mixture of alkyl esters (for example

  from C1 to C8) fatty acids derived from natural, vegetable or animal oils.

  More particularly in the formulations of the invention, said demulsifying agent is present in a proportion of 0.5 to 100% by weight of pure active material; said wetting agent in a proportion of 0 to 50% by weight of pure active material; and said solvent (or diluent) in a proportion of 0 to 99.5% by weight; the assembly having a concentration of pure active materials of 0.5 to 100 g, preferably of 0.01 to 10 g,

  per 100 g of said organic base.

  The demulsifying agent (or "emulsion breaker") may consist on the one hand of at least one non-ionic amphiphilic composition obtained by reaction of at least one oil

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  vegetable, optionally polymerized, on at least one amino alcohol. Such composi-

  tions have been described in French patent FR-B-2 768 732 in the name of the same applicant.

  In the preparation of such compositions, all vegetable oils may be suitable.

  Preferably, highly unsaturated oils such as linseed oil, safflower oil, grapeseed oil, Chinese wood oil, sunflower oil and the like will be used.

  their mixtures. Linseed oil is preferred.

  These vegetable oils are used as such or polymerized. Polymerized vegetable oils (commonly called "stand oils") are obtained by heat treatment of the highly unsaturated vegetable oils mentioned above, under conditions such that there is no oxidation. Linseed oil (preferably refined) is generally used, but it is possible to use safflower oil, grape seed oil, Chinese wood oil, sunflower oil or their mixtures. The polymerized vegetable oils can have, after polymerization, a viscosity at 20 ° C. of between 5 and 60 Pa.s. For example, the heat treatment of a refined linseed oil at a temperature of 290-300 C gives in 6 to 12 hours a product with a viscosity of

Pa.s at 25 C.

  The amino alcohols used to prepare the amphiphilic compositions which can enter into the composition of the formulations of the invention are generally amines or polyamines comprising one or more alcohol functions and optionally one or more

ether functions.

  For example, the amino alcohols can correspond to the following formulas HO-CmH2m-NH2 HO-CmH2m-NH-CkH (2k + 1) (HO-CmH2m-) 2-NH (HO-CmrH2m-) p CH (3-p) NH2

avecm = 2A6; k = 1 to 6; p = 2or3.

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  In particular, there may be mentioned: monoethanolamine: OH- (CH2) 2-NH2, monopropanolamine: OH- (CH2) 3-NH2, monoisopropanolamine: CH3-CH (OH) -CH2NH2, 2-amino-1- butanol: CH3-CH2-CH (NH2) -CH2-OH, 1-amino-2-butanol: CH3-CH2-CH (OH) - CH2-NH2, N-methyl-ethanolamine: CH3-NH- (CH2 ) 2-OH, Nbutyl-ethanolamine: CH3- (CH2) 3-NH- (CH2) 2-OH, pentanolamine, hexanolamine, cyclohexanolamine, polyalkanolamines or also polyalkoxyglycolamines, of formula: OH- (CH2 -CH2-O-) nCH2-CH2-NH2 (n between 1 and 30) and amino polyols such as: diethanolamine: (OH -CH2-CH2-) 2 NH, diisopropanolamine: (CH3-CH (OH) - CH2) 2-NH, or

  trihydroxymethylaminomethane: ((HO) H2C-) 3C-NH2.

  The synthesis of the compounds of the invention can be carried out by reaction of an excess of amino alcohol, preferably diethanolamine, on a vegetable oil, as it is or polymerized, preferably linseed oil polymerized. Preferably, the reaction is carried out in the absence of solvent and generally at a temperature above about 100 C, and preferably between 100 and 200 C. However, if the viscosity of the

  reaction medium is too high, the reaction may be carried out in the presence of a solvent.

  The demulsifying agent (or "emulsion breaker") can also consist of at least one mixture of alkyl esters (for example from C1 to C8) of fatty acids derived from natural, vegetable or animal oils. In this case, all oils can

  also suitable, but preference will be given to rapeseed oil. The demulsifying agent

  sionnant can, of course, consist of various proportions (a) of at least one nonionic amphiphilic composition obtained by reaction of at least one vegetable oil, optionally polymerized, on at least one amino alcohol and (b) at least minus a mix

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  alkyl esters of fatty acids derived from a natural oil, for example of vegetable origin. When it is present in the organic-based formulations of the invention, the wetting agent can be chosen more particularly from anionic surfactants such as

  s sodium dialkyl sulfosuccinates, for example sodium dioctyl sulfosuccinate.

  The solvent (or diluent) optionally present in the formulations of the invention can be any organic base. It can be chosen more particularly from the

  petroleum fractions (such as kerosene), alcohols and hydro-

  alcoholics. It can also be chosen from alkyl esters of carboxylic acids.

  long chain liquids, such as 2-ethylhexyl esters of an acid cut

  carboxylic 8 to 10 carbon atoms, which will be designated below by 2-

  éthylhexylC8C10l. It can also be chosen from plant derivatives such as the compositions of alkyl esters (for example from C1 to C8) of fatty acids derived from oils

  vegetable, for example the methyl esters of rapeseed oil.

  In the demulsifying formulations of the invention, the compositions of alkyl esters (for example from C1 to C8) of fatty acids derived from vegetable oils can therefore play the role of demulsifying component proper or of solvent (or diluent). The proportion of solvent (or diluent) in the formulations of the invention is preferably

between 20 and 40% by weight.

  The base in which the composition defined above is used is generally a mineral oil or an oil of plant origin, preferably non-polluting. As examples of oils of vegetable origin, mention may be made of mixtures of alkyl esters (for example from C1 to C8) of vegetable oils, such as mixtures of methyl esters of

Rapeseed oil.

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  The organic base used can be an oil identical to that of mud. In this case, it is possible, for example, to use a mineral oil, such as HDF 2000 oil or EDC oil (sold by the company Total Solvant), or a vegetable oil, such as BDMF oil (mixture of methyl esters). rapeseed oil sold by TotalFina Oléochimie). Alternatively, the organic base as defined above may itself serve as a solvent (or diluent) for the constituents (demulsifier and / or wetting agent) of the

formulations of the invention.

  The invention also relates to the use of the demulsifying formulations described.

  above for the treatment of drains drilled in oil mud.

  In this application, the treatment formulations according to the invention are chosen correlatively to the mud formulation so as to be compatible with the emulsifying systems and wetting agents generally used for dispersing the solids in the mud. The demulsifying formulations according to the invention meet selection criteria which can be verified by implementing the following determinations: * characterization of the cake destructuring action: in crystallizer and in static filtration cell by the "Differential" technique Scanning Calorimetry "(DSC) and cryomicroscopy; * compatibility of formation fluids (oil and brine), treatment (oil-based demulsifying formulation) and drilling fluids (mud filtrate

  oil-based drilling): study of the formation of emulsions in situ.

  The ability of a demulsifying formulation to be used according to the invention is mainly

  duly verified by the DSC technique. This technique is described in detail in "Use of the DSC for the characterization of the stability of water in petroleum emulsions" (C. Dalmazzone, H. Séris - Journal of the French Petroleum Institute, vol. 53, n 4,

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  1998). The technique is implemented on cake samples before and after

  treatment to assess the breaking of the emulsion within the cake.

  The DSC thermal technique is generally used to determine the composition of water-in-oil emulsions, because it makes it possible to distinguish free water from emulsified water (free water crystallizes at much higher temperatures than droplets of emulsion water). This technique is based on the solidification and melting properties of the droplets and the medium in which they are dispersed. The information obtained concerns: * the type of emulsion: simple (water-in-oil or oil-in-water) or multiple (water-in-oil-in-water or oil-in-water-in-oil); * the quantity of liquid and its state: bound or dispersed or free; * the compositions of the free and dispersed phases; * the average diameter of the droplets and their evolution as a function of time due to the coalescence or ripening of Ostwald; * transfers of material between droplets due to their difference in composition. The conditions to be fulfilled for the demulsifying system are: * compatibility of the oil sludge filtrate, reservoir fluids and

  treatment. The proportion of each phase varies to be able to determine the forma-

  tion of emulsions in the form of a ternary diagram. The emulsion formation is

  characterized by "Bottle Test" type tests,.

  * destructuring of the cakes obtained in API tests by breaking the emulsion. The destructuring of the cakes is evaluated by analysis of the DSC curves and by cryomicroscopy.

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Examples

  The following examples illustrate the invention without limiting its scope. In these examples 4 types of formulations were tested:

  Example 1: methyl esters of pure rapeseed oil.

  Example 2: non-ionic amphiphilic composition obtained by reaction of linseed oil polymerized on diethanolamine, at 50% by weight in methyl esters of oil

rapeseed.

  Example 3 non-ionic amphiphilic composition obtained by reaction of linseed oil polymerized on diethanolamine, at 50% by weight in a mixture of equal weight of rapeseed methyl esters and 2ethylhexylC8C10, in 1 g / solution 100 ml in 2-ethylhexylC8C10l. This formulation therefore contains 50% by weight of demulsifier

  pure and, in all, 50% by weight of solvents. It is used in solution in 2-

  ethylhexylC8C10 at a concentration of 10 g / I.

  Example 4 The formulation has the following composition: demulsifier: 5% by weight of non-ionic amphiphilic composition obtained by reaction of linseed oil polymerized on diethanolamine, the wetting agent: 25% by weight of aerosol OTS (70% by weight of sodium dioctyl sulfosuccinate in a petroleum cut) and 20% by weight of Celanol DOS (65% by weight of sodium dioctyl sulfosuccinate in a hydroalcoholic mixture);

  - diluent: 50% by weight of Ketrul 210 (deodorized kerosene cut).

  - the whole being in solution at 1 g / 100 ml in a HDF2000 mineral oil (

mud).

  This formulation therefore contains 5% by weight of pure demulsifier, 30.5% by weight of pure wetting agent and, in all, 64.5% by weight of solvents. It is used in solution

  in oil at a concentration of 10 g / I.

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  Three types of tests are used to evaluate the effectiveness of the treatment on the destructuring of oil mud cakes: destructuring test in crystallizer, static filtration test in cell and compatibility test between reservoir fluids, fluid

  and the processing fluid.

  Destructuring test for cakes in a crystallizer The kinetic aspects of the destructuring of cakes have been studied on a formulation

  commercial oil-based mud.

  Principle: The oil-based mud is filtered on filter paper in a static filtration cell according to the API procedure at a temperature of 80 C and under a pressure difference of 35 bars for one hour. Pieces of the cake obtained are placed in crystallizers in contact with 20 ml of treatment solution for variable times at room temperature. The breaking of the emulsion within the cake is evaluated thanks to the

DSC technique.

  Pieces of filter paper supporting the cake are cut with a scalpel. The mass of the samples is approximately 10 mg, weighed precisely. The sample is placed with forceps in an aluminum capsule. Particular care is taken when handling the sample (cutting with filter paper, introduction into the capsule) to avoid

  damage the cake mechanically.

  The cell is then introduced into the furnace of the DSC apparatus alongside an empty reference cell. The cell then undergoes a cooling-heating cycle from 20 C to -120 C. The heat flow Q (in W / g) is recorded as a function of the temperature T (in C). A calibration is carried out beforehand with a cell containing brine at the same CaCl2 concentration as the mud. The presence of water in the sample is

  detected by the peaks of crystallization of the brine.

  Qualitatively, the temperature corresponding to the peaks makes it possible to evaluate the state of the water in the sample, the free water crystallizing at higher temperatures than water.

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  emulsified. On the other hand, the shape of the peak makes it possible to rule on the polydisperse (irregular peak or with a shoulder) or monodisperse (regular and tapered peak) character of

  the emulsion within the cake, which gives information on its stability.

  From a quantitative point of view, the position of the peaks makes it possible to assess the fineness of the emulsion (the droplets have a diameter the smaller the lower the crystallization temperature). In addition, the size of the peaks provides access to the mass of water present in the sample. Table 1: Sludge system used BAROID -20 formulation Base oil Mineral oil

HDF 2000 ()

  Brine Water at 24% by weight of CaCI2 Static filtration test The sludge formulation A (BAROID) is filtered according to the API procedure (API standard 13) at a temperature of 80 C and under a pressure difference of 35 bars. After filtration of 300 ml of mud for one hour, the cell is depressurized, emptied of the mud, rinsed with 200 ml of treatment solution, then filled with 300 ml of treatment solution. The cake inside the cell is left in contact with the treatment solution for a variable time at 10 bars and at 80 C ("soaking time"), before

start a new filtration.

  Compatibility test In order to avoid additional damage to the formation on the wall, it is advisable to control the formation or not of emulsions in situ by choosing a treatment fluid compatible with the reservoir fluids (brine and oil) and the mud filtrate.

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  In this example, the brine (NaCl, 20 g / l) and an organic phase are brought into contact

  composed of tank oil, sludge filtrate and demulsifier.

  The filtrate is reconstituted from the base oil and the surfactants from the mud. Is brought into contact, at equal volume: a mixture of 80 ml of filtrate - 20 ml of emulsion (3 ml of NaCl brine 20 g / I in 17 ml of reservoir oil) and 100 ml of treatment product. Agitation is manual (1 minute) and the emulsion is poured into a separating flask.

  The results obtained with each of the tested formulations are described below.

Example 1:

  The destructuring test in a crystallizer is carried out with formulation 1. The emulsion is broken completely after 24 hours of contact time, which is materialized by the appearance of a peak of free water at around -40 ° C. see Figure 1 for 24 hours and Figure 2 for

one week).

Example 2:

  Tests in crystallizer From a qualitative point of view, at room temperature, even at short contact times

  (24 hours), there is a clear change in the quality of the emulsion within the cake.

  In the case of formulation 2, the initial peak of emulsified water (-80 C) has disappeared. Two peaks are observed together at -69 C and -57 C. This increase in temperature signals a larger droplet size, there was coalescence of the droplets within the cake. The emulsion appears more clearly polydisperse (presence of two sizes of droplets) (cf. Figure 3). After a week of contact time, the cake is

  clearly unstructured (see Figure 4).

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Example 3:

  Like the formulation of Example 2, the formulation of the present example makes it possible to obtain a very rapid breaking of the emulsion within the cake, observed thanks to the crystallizer test (24 hours and one week): the peak of the emulsified water has indeed moved towards -40 C, indicating the presence of very large droplets likely to coalesce

  to form free water (see Figure 5 and Figure 6).

Example 4:

Tests in crystallizers:

  A sample of the treated cake is analyzed by the DSC technique as above.

  The breaking of the emulsion within the cake is confirmed by the cooling cycle -

  heating obtained in DSC. For a contact time of 24 h, a swelling is observed on the peak of emulsified water: the emulsion becomes polydisperse (cf. FIG. 7). For a contact time of one week, we observe different peaks on the crystallization curve

  : The emulsified water in the form of very fine droplets is materialized by the peak at -

  80 OC, while a bulge around -60 OC indicates the presence of fine droplets coalescing. The two small pointed peaks respectively reveal the presence of large droplets and free water from the breaking of the emulsion. (Cf.

Figure 8).

  Static filtration tests In Figure 9, the volume V has been plotted in ml as a function of the time root in

  minutes Rt) for different contact times before filtration (1 h, 2 h and 4 h).

  Comparative Example 5 The same type of test was carried out with a treatment product containing 6% by weight of the commercial product DM1 (supplied by the company BAROID) in solution in 64% in

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  weight of HDF 2000 base oil and 30% by weight of a PARAGON aromatic solvent.

  The results shown in Figure 9 by the drainage curve as a function of time

  show a lower filtration slope than for the formulations of the invention.

  Figure 10 presents the characterization in DSC of the cake treated in static filtration after a contact time of 2 hours: the destructuring of the cake is revealed by the coalescence of the droplets within the emulsion (displacement of the crystallization peak

  towards higher temperatures).

  Compatibility test: The sludge formulation and the treatment solution are brought into contact at equal volume according to the protocol mentioned above. There is immediate breakage of the emulsion formed.

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Claims (13)

  1. Organic demulsifying formulation characterized in that it comprises: - at least one constituent chosen from non-ionic amphiphilic compositions   obtained by reaction of at least one vegetable oil, optionally polymeric   sée, on at least one amino alcohol, and the alkyl esters of fatty acids derived from natural, vegetable or animal oils; - optionally at least one wetting agent; - and optionally at least one solvent;   - the whole being mixed in an organic base.   2. Formulation according to claim 1 characterized in that: - said demulsifying agent is present in a proportion of 0.5 to 100% by weight of pure surfactant; and - said wetting agent is present in a proportion of 0 to 50% by weight of pure surfactant; - Said solvent is present in a proportion of 0 to 99.5% by weight; - the whole having a concentration of pure active ingredients of 0.5 to 100 g   per 100 g of said organic base.   3. Formulation according to claim 1 or 2 characterized in that said demulsifying agent   sionnant comprises at least one nonionic amphiphilic composition obtained by   reaction of polymerized linseed oil on diethanolamine.   4. Formulation according to claim 1 to 3 characterized in that said demulsifying agent   sionnante comprises at least one mixture of methyl esters of rapeseed oil.   5. Formulation according to claim 1 to 4 characterized in that said wetting agent   is chosen from anionic surfactants. 17 2817165   6. Formulation according to claim 5 characterized in that said wetting agent is   sodium dialkyl sulfosuccinate.   7. Formulation according to one of claims 1 to 6 characterized in that said solvent   is chosen from petroleum fractions, alcohols and hydro-alcoholic mixtures, from alkyl esters of long chain carboxylic acids and from   alkyl ester compositions of fatty acids derived from vegetable oils.   8 .. Formulation according to claim 7 characterized in that said solvent is a   mixture of methyl esters of rapeseed oil.   9. Formulation according to one of claims 1 to 8 characterized in that said base   organic is a mineral oil or an oil of vegetable origin.   10. Formulation according to claim 9 characterized in that said organic base is non-polluting.   11. Formulation according to claim 9 or 10 characterized in that said oil   of vegetable origin is a mixture of methyl esters of rapeseed oil.   s5 12. Formulation according to one of claims 1 to 11 characterized in that, the   formulation being used for the treatment of drains drilled in oil mud, the base   organic of said formulation is an oil identical to that of mud.   13. Use of an organic base demulsifying formulation according to one of the   Claims 1 to 12 in the treatment of a drain drilled in oil mud.